About 3 or 4 years ago I started getting a large influx of scam calls to my cell phone whereas previously I had none at all. All of them were using Caller ID spoofing with the spoofed number basically the same as mine just with a different digit or two in the last four. I would get three or four calls a day, and then not get any for a couple days, then get one or two, then back to three or four. Call blocking does not work as the spoofed CID info always changes.
A couple years ago I did the big no-no and started answering these junk calls when I had some free time, just to play around and waste their time. You attempt to waste my time, I’ll waste yours. I can usually have them going for 10 – 15 minutes before they realize I’m screwing with them. My longest was a fake Microsoft call which lasted 22 minutes and ended with me saying ‘what do you want me to do after I click the big blue E’, after first calling it the calling it a ‘little orange Q’ and the fake tech said ‘next, I want to take your keyboard and mouse and shove them up your ass’ and then he hung up. I was on the floor laughing.
Not sure if it was a coincidence or not, but after a couple weeks of answering just about every junk call I received and, the calls dropped off considerably. I went a little over an entire month without getting a single junk call. Then the started happening again, but in far fewer numbers. A few months ago I installed the YouMail app and had it filter out all calls except from numbers in my contacts. If the incoming CID info doesn’t match my contacts it goes to a ‘this number is out of service’ message. Supposedly automatic dial systems can recognize the tone the proceeding the message and it gets removed from the system. No way to verify that but that is the heresy around the interwebs, and it may be coincidence or a placebo effect, but the number of junk calls further got reduced. I’ve maybe got three or four total so far in this young year of 2019 after uninstalling YouMail. Due to work reasons I cannot keep that as a permanent solution.
I wish there was additional call screen/AA functionality. If you are in my contacts list you can ring me fine, if not you have to enter a random 3 digital number if you want to talk to me. To me that is the best solution for stopping scam robocalls.